Raman, SarojaJanka, Mesfin2018-06-202023-11-092018-06-202023-11-091994-06http://etd.aau.edu.et/handle/12345678/2391The kinetics of dissociation of pentacyano paranitrosophenol and 4-nitroso N,N'-dimethyl aniline ferrate(II} complexes was studied under three different conditions: i) substitution of PNP and PNA with excess pyridine, ii} acid catalysed substitution of PNP and PNA and iii) Hg(II) promoted aquation of the nitroso complexes. The rates of dissociation of Fe [CN) 5PNA3- and Fe [CN) sPNp3- increased with the concentration of pyridine and reached limiting values at pyridine concentrations> 0.5 M. The pseudo first order rate constants varied as k=k1 k2 [PY] where k, is the dissociation rate constant of the complexes, and k_l and k2 are the association rate constants of Fe [eN) 53- with Land py, respectively. The enthalpy and entropy of activation are AH# = 95 ± 4 kJ mol-1 , AS# = 22 ± 7 J mol-1 K-1 for Fe[CN)sPNA3- and AH# = 92 ± 3 kJ mol-1 , AS# = 14 ± 4 J mol- ' K- 1 for Fe [CN)5PNp3-. The rateenPentacyano P-Nitrosophenol and PentacyanoThesis